The superconducting memory having an operating principle which is close to the one of the present invention is the "vortex memory" operated in liquid helium temperature (4.2K) utilizing a metal low-temperature superconductor, which has already been proposed and tested.
The vortex memory is taught in the following documents: "Abrikosov vortex memory"; K. Miyahara et al. (NTT) Appl. Phys. Lett. 47(7), P.754 (1985); U.S. Pat. No. 4,764,898, Aug. 16 (1988) (NTT); Japanese Patent No. 1668743, May 29, 1992 and eleven other patents (NTT).
The technique taught by said documents utilized low-temperature superconductors, and by the prior art, a superconducting RAM operated in a temperature of over 20K could not be realized. In the present invention, such memory is realized and a data processing device of high speed and large capacity operated in a temperature of over 20K is realized.